# All Questions

18,420 questions
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### Guessing 3DES key from weak keys [closed]

I have CPU access which has a static cipher key in register 0x00. I want to guess the key present in register 00 which is actually a master key used to encrypt/decrypt all other keys. Is there any way ...
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### Isogeny of elliptic curve

If we have two elliptic curves $E$ and $E'$ and the points of both elliptic curves are same. Then all the points of $E$ map to all the points of another elliptic curve $E'$. For example $E$ has ...
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### Is it possible for an attacker to determine the original input to the S-Boxes in DES?

I am learning about DES, a Feistel 64-bit block cipher with 16 rounds. Is it possible that an intruder can determine the original input to the S-Boxes?
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### What is the significance of $\prod \limits_{i=1}^{t}m_i > p \prod \limits_{i=1}^{t-1}m_{n-i+1}$ in Asmuth–Bloom threshold SSS?

In this paper by Asmuth–Bloom on threshold SSS, the algorithm is as follows: Shares Distribution To distribute $n$ shares of a secret $K$ among the set of participants $P = \{ p_i : 1 ≤ i ≤ n\}$, ...
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### Guessing the key in AES256-GCM?

I assume that my case is weird but I've the following information: IV: 0x263e or 0x3e26 Auth tag: 0x25 AES256-GCM encrypted payload: 0x4eec96df534ade4c013a AES256-GCM decrypted payload: ...
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### Patarin’s H-Coefficient Technique

I have come across many paper that applies Patarin’s H-Coefficient Technique in various cryptographic securities (KPA, CPA, CCA,...). I am asking kindly if someone could explain it simple with ...
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### Problem in generation of keys in KP-ABE

In KP-ABE the owner encrypts the message using attributes say a'. The Attribute authority(AA) designs an access structure and implants that access structure in keys generated by AA for the user. So, ...
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### How does the order of a group, it's torsion subgroup and the co-factor link?

Given an elliptic curve that defines some group of non-prime order, with co-factor h. Would it then have a h-torsion subgroup? What are the implications for ECC ...
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### Python 3.x Cryptography Fernet / AES256 Is this safe and secure? [migrated]

I wrote this code to make easy use of the Python library Cryptography https://cryptography.io/en/latest/ to encrypt data Is this safe and secure given the user inputs a strong password? ...
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### How is the Swiss post e-voting system supposed to work, and how was it wrong?

I read that the Swiss post had an e-voting solution developed, made it possible to obtain the source code for review, and that vulnerabilities were found. Apparently we are not talking about the ...
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### Key-Exchange in Steganography

I know there are key-exchange methods in Cryptography. But in case of Secret-key Steganography, what actually stego-key means and how can we use the key and once used how we exchange that with the ...
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### How is an IV used in a Merkle-Damgard construction- Explicit example

I am interested to know how an IV is used in this simple Merkle-Damgard construction. I am referring to this image from the associated Wikipedia page as I explain further. For the purpose of ...
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### How many bytes of data does AES 256 encrypt at one time?

Since the block size of AES 256 is 256, how would we calculate the bytes of data AES 256 encrypts at one time?
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### Key confirmation and other benefits of double ratchet

I'm trying to understand a comment from the Signal blog post Advanced cryptographic ratcheting. This article uses the term OTR ratchet to refer to a simple asymmetric DH ratchet, where Alice ...
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### Can anyone elaborate why KP-ABE is better than CP-ABE for television program broadcasting?

I know the difference between KP-ABE and CP-ABE. I am not able to understand why KP-ABE is better for broadcasting than CP-ABE ?
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### Problems in installing Charm Crypto on Raspberry Pi 3 [migrated]

I am trying to install Charm crypto library on Raspberry Pi 3, everything works fine but make and make install fails as shown in attached screenshots 2 and 3. The configuration is successful . The ...
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### Disabling the AES cipher suites without ECDHE key exchange algorithm [migrated]

Currently, we are having below cipher suites used in our platform. AES128-GCM-SHA256 AES128-SHA256 AES128-SHA ECDHE-RSA-AES128-GCM-SHA256 ECDHE-RSA-AES128-SHA256 ECDHE-RSA-AES128-SHA Post ...
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### Cryptanalysis of an OTP RFID tag transmission using multiple transmissions [duplicate]

A scanner encrypts a 32 bit message 'x' using a secret 32 bit key 's1' and sends the resulting cipher y= x XOR s1 to an RFID tag. The Tag decrypts the message 'x' ,and then encrypts the message 'x' ...